Unfortunately it seems the new software is a touch too enthusiastic as there
are quite a few reports of it rejecting Apple supplied cables, Rick Maybury
says

A few days ago I updated my iPhone 5 to IOS 7 and now, when I plug it in to charge, it tells me that the lead is not Apple approved and may not work properly. If I don't press ‘Dismiss this Message’ the phone won't charge. I am using the lead and plug that came with the phone. My wife's iPhone 4 charges normally. Any ideas?

Michael Ulliott, by email

This new feature in iOS 7 is supposed to prevent the use of unlicensed and potentially dangerous accessories that use the Lightning Connector, which explains why your wife’s iPhone 4 is unaffected as this uses the old style 30-pin Dock connector.

Unfortunately it seems that the new software is a touch too enthusiastic as there are quite a few reports of it rejecting Apple supplied cables, as well as cables and chargers that worked perfectly well under iOS 6.

It is worth contacting Apple Support and providing your iPhone is still under warranty there is a fair chance that your charger and cable will be replaced free of charge.

You are fortunate that you can still charge your iPhone, albeit under protest. Others have not been so lucky but there are a number of workarounds. Charging the iPhone on a computer running the most recent version of iTunes works for some.

You may have to switch the phone on and off a few times, dismiss any ‘…not certified…’ warnings but when ‘Trust This Computer’ appears it should start charging. Unplugging and re-inserting the Lightning connector and dismissing warnings several times may also succeed, and bizarrely, some users have suggested that charging the phone with the SIM card removed works for them.

In the end, however, the best way to avoid this annoying problem is to use Apple’s own charge cable, or approved accessories that carry the MFI (Made for iPhone/iPad) logo.